As host network devices can also be instantiated via the monitor, errors
should then be reported to the related monitor instead of stderr. This
requires larger refactoring, so this patch starts small with introducing
a helper to catch both cases and convert net_client_init as well as
net_slirp_redir.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NMark McLoughlin <markmc@redhat.com>